MOZ-IN-3 is an inhibitor of lysine acetyltransferase 6A (KAT6A/MOZ) and KAT6B/MORF (IC50s = 8 and 28 nM, respectively). It is selective for KAT6A and KAT6B over KAT5 and KAT7 (IC50s = 224 and 342 nM, respectively). MOZ-IN-3 induces cell cycle arrest in and inhibits proliferation of mouse embryonic fibroblasts (IC50 = 2.4 μM) and inhibits proliferation of EMRK1184 lymphoma cells (IC50 = 2.3 μM). It induces genetic and morphological changes associated with cellular senescence without inducing DNA damage, apoptosis, or necrosis. MOZ-IN-3 (10 μM) decreases global levels of acetylated histone H3 lysine 14 (H3K14Ac) by 49% and reduces H3K9Ac levels at the transcription start sites of Ezh2, Melk, and E2f2.